Aircraft systems Flashcards
(27 cards)
Reciprocating engines operate on what principle
changing chemical energy into mechanical energy
the two primary designs of a reciprocating engine
spark ignition and compression ignition
why is a compression engine a viable alternative?
utilizing readily available jet fuel that is cheaper
what is the main difference between the mechanical components of a spark ignition and compression ignition?
the process of igniting the fuel, uses a spark plug to ignite a premixed fuel air mixture (the weight of the fuel to the weight of the air). A compression air engine compresses the air in the cylinder, raising its temperature to a degree necessary for automatic ignition, into the cylinder.
The two engine designs can be further classified as: what?
1) Cylinder arrangement with respect to the crankshaft– radial, in line, v type, or opposed.
2) Operating cycle– two or four
3) method of cooling– liquid or air
the main advantage of a radial engine
a favorable power to weight ratio.
on a propeller the greatest angle of incidence is where
hub has the greatest angle of incidence and pitch
The tachometer indicator shows what
the indicator of engine power, direct indication of the engine and propeller rpm
what is the main advantage of a constant speed propeller?
more efficient than other propellers because it allows selection of the most efficient rpm for given conditions
The manifold pressure gauge shows what
measures the absolute pressure of the fuel to air mixture inside the intake manifold absolute pressure (MAP)
for any given rpm there is a manifold pressure that should not be exceeded. for what reason?
If manifold pressure is excessive for a given rpm, the pressure within the cylinders could be exceeded, placing undue stress on the cylinders. if repeated to frequently this stress can weaken the cylinder components and eventually cause engine failure.
what order to add power or rpm
reduce manifold pressure, reduce prop,
increase prop, increase manifold pressure.
in a propeller over speed condition
some reduction in airspeed may result in the ability for continued safe flight and landing.
The induction system does what?
brings in air from the outside, mixes it with fuel, and delivers the fuel-air mixture to the cylinder where combustion occurs.
where is the alternate air door in the cessna
inside the engine cowling and opens automatically
what are the two types of induction systems commonly used in small aircraft engines
the carburetor system mixes the fuel and air in the carburetor before this mixture enters the intake manifold. The fuel injection system mixes the fuel and air immediately before entry into each cylinder or injects fuel directly into each cylinder.
Carburetors are separated into what two categories
float type and pressure type
what are disadvantages of the float type carburetor
function poorly during abrupt maneuvers, discharges fuel at low pressure and leads to incomplete vaporization and difficulty in discharging fuel into some types of supercharged systems. the chief disadvantage is its icing tendency.
engine roughness with a rich mixture at a high density altitude results in what?
engine roughness and appreciable loss of power. due to spark plug fouling and carbon buildup on the plugs.
An overly lean mixture can cause what?
detonation, which can result in rough engine operation, overheating, and or loss of power.
carburetor ice occurs do to what
the effect of fuel vaporization and the decrease in air pressure in the venture, which causes a sharp temperature drop in the carburetor. If water vapor condenses when the carburetor is at or below freezing, ice may form on the internal surfaces of the control valve.
what is the first indication of carburetor ice in a fixed prop
a drop in a rpm
what is the first indication of carburetor ice in a constant speed propeller
a drop in manifold pressure
a fuel injection system usually incorporates six basic components
an engine driven fuel pump, fuel air control unit, a fuel manifold (fuel distributor), discharge nozzles, an auxiliary fuel pump, and fuel pressure/flow indicators.
